A typical prior art device is depicted in FIGS. 11 and 12. Main housing 1 comprises bulb socket 2 and connector socket 3 at right angles to each other. Connector terminal 4 is located within connector socket 3 and is adapted to be electrically connected to power supply connection B. Bulb terminal 5 is located in bulb socket 2 and is adapted to receive the contact portion of bulb A.
To assemble the device, connector terminal 4 is inserted into housing 1 in the horizontal direction as shown in FIG. 11. Correspondingly, bulb terminal 5 is inserted into bulb socket 2 in a vertical direction as shown in FIG. 11. Fitting hole 4B is formed in leading end 4A of connector terminal 4 and insertion end 5A of bulb terminal 5 is inserted therethrough. In this way, the parts are locked together and electrical contact is maintained.
However, such prior art devices suffer from some important defects. Both terminals 4 and 5 are pressed into main housing 1 in their respective directions. As a result, their ability to displace relative to one another is extremely limited. Such movement is further limited by the insertion of end 5A into fitting hole 4B. Thus, there is little or no flexibility between the two terminals and also between either of the terminals and the main housing. Since the housing is normally made of synthetic resin, it has a tendency to expand and contract as the ambient temperature rises and falls. Since the device is intended for use in an automobile, these temperature differences can be substantial. When this occurs, undesirable stresses are induced, especially between terminals 4 and 5 at their point of connection 4A, 5A.